Tizen reached 1.0 only recently, but there's already a Tizen Conference going on - and during that conference, Samsung had a relatively barebones reference device running Tizen 1.0. The Handheld Blog has a seven minute video of the device in action, and while I'm very happy big players are investing in all these alternative platforms, I do have to wonder - how viable are they?

Community support is just too little to ensure OS viability in the break neck smartphone environment. They are simply moving too slow and lack UI competencies.
Look what happened with full OSS Openmoko, they had a year headstart before IPhone and haven't even managed to produce just a working phone basics, nevertheless working stable apis and killer apps.

There is no need to equate community driven development, and the lack of support. Some companies can actively support community projects. Or base their derivative works on them, and provide support for the final product. My point about community was related to those who are in charge of the project direction. I have more trust in communities who use open development model, than in corporations who develop and decide stuff totally in secret (Tizen development is not open at all, and community has no say in any decisions).

Mer project proposed to develop community driven Linux core, on which others can build final products. Plasma Active for example already use it for their upcoming Vivaldi tablet, and they have several companies who participate in Plasma Active work. Providing support can be viable, but at least they rely on something that won't likely to be dropped, because MS bribes one of the parties (like Nokia), or they suddenly have change of heart (like Intel).